Also keep in mind that not everybody has Java.
You'd be surprised. Many people install it without even noticing respectively caring.
On the general issue of the chat, it's basically same ol', same ol'... since it's been started way back, it's had a hard time seeing some activity and the problematic nature of IRC clients and its webinterfaces, as correctly pointed out by you, doesn't make it a convenient or enjoyable chat experience.
In all honesty, something like a jabber chat room might be more interesting... yet for obvious reasons - server load - it won't be an option either unfortunately.